GL494

GL494 GL494 PWM CONTROL CIRCUIT Description The GL494 incorporates on a single monolithic chip all the functions required in the construction of a pulse-widthmodulation control circuit. Designed primarily for power supply control, the GL494 contains an on-chip 5-volt regulator, two error amplifiers, adjustable oscillator, deadtime control comparator, pulse-steering flip-flop, and output-control circuitry. The uncommitted output transistors pro-vide either common-emitter or emitterfollower output capability. Push-pull or single-ended output operation may be selected through the outputcontrol function. The ar-chitecture of the GL494 prohibits the possibility of either output being pulsed twice during push-pull operation. Pin Configuration NONINV INPUT INV. INPUT FEEDBACK DEAD TIME CONTROL Cr Rr GND C1 1 2 3 4 5 6 7 8 16 15 14 13 12 11 10 9 NON INV INPUT INV. INPUT REF. OUT OUTPUT CONTROL Vcc C2 E2 E1 Features — Complete PWM Power Control Circuitry — Uncommitted Outputs for 200mA Sink or Source — Output Control Selects Single-Ended or Push-Pull Operation — Internal Circuitry Prohibits Double Pulse at Either Output — Internal Regulator Provides a Stable 5V Reference Supply — Variable Dead-Time Provides Control Over Total Range Function Table Output Control Grounded At Vref Output Function Single-ended or Parallel Output Normal Push-Pull Operation Block Diagram RT CT OSCILLATOR OUTPUT CONTROL (See Function Table) DEAD TIME CONTROL 0.1V (4) PULSE STEERING FLIP FLOP Q T Q P WM COMPARATOR VCC (12) REFERENCE REGULATOR (13) ERROR AMPLIFIERS NONINVERTING(1) + INPUT INVERTING INPUT (2) − E1(9) C1(8) ERROR AMP1 NONINVERTING(16) INPUT INVERTING INPUT FEEDBACK (15) (3) + − ERROR AMP2 REF OUT (14) GND (7) E1(10) C2(11) 1 GL494 Absolute Maximum Ratings Supply Voltage, VCC ……………………………………………………………………….. 41 Amplifier Input Voltage ……………………………………………………………….. VCC +0.3 Collector Output Voltage ……………………………………………………………………… 41 Continuous Total dissipation at (or below) 25 °C ………………………………………. 1000 Operating Free-Air Temperature Range ……………………………………………… -20 to 85 Storage Temperature Range ……………………………………………………….….. -65 to 150 Collector Output Current ………………………………………………………………….. 250 V V V mW °C °C mA Recommended Operation Conditions PARAMETER Supply Voltage, VCC Amplifier Input Voltage, V1 Collector Output Voltage, Vo Collector Output Current (Each Transistor) Current Into Feed back Terminal Timing Capacitor, C T Timing Resistor, R T Oscillator Frequency 0.47 1.8 1 MIN 7 -0.3 MAX 40 VCC -2 UNIT V V V mA mA nF KΩ 40 200 0.3 10,000 500 300 KHz °C Operating Free-Air Temperature -20 85 Electrical Characteristics (Temperature −20 ~ 85°C , VCC =15V, f=10KHz) Reference Section PARAMETER Output voltage ( Vref ) Input regulation Output regulation Output Voltage change with temperature Short-circuit Output current(2) TEST CONDITIONS IO = 1mA VCC = 7 V to 40V, TA = 25°C IO = 1 to 10mA, TA = 25°C TA = −20°C to 85°C Vref = 0 MIN 4.75 TYP(1) 5 2 1 0.2 35 MAX 5.25 25 15 1 UNIT V mV mV % mA Oscillator Section PARAMETER Frequency Standard deviation of frequency (3) Frequency change with Voltage Frequency change with temperature TEST CONDITIONS C T = 0.01µF , R T = 12 kΩ MIN TYP(1) 10 10 0.1 MAX UNIT KHz % % All values of VCC , C T , R T , TA Constant VCC = 7 V to 40V, TA = 25°C C T = 0.01µF , R T = 12 kΩ TA = −20°C to 85°C 2 % 2 GL494 Dead Time Control Section PARAMETER Input bias current (pin 4) Maximum duty cycle, Each output Input threshold voltage (pin 4) TEST CONDITIONS VI=0 to 5.25V VI ( pin 4) =0V MIN TYP(1) -2 MAX -10 UNIT µA 45 3 0 3.3 % V V Zero duty cycle Maximum duty cycle Error Amp Sections PARAMETER Input offset voltage Input offset current Input bias current Common-mode input voltage range Open-loop voltage Amplification Unity-gain bandwidth Common-mode rejection ratio Output sink current (pin 3) Output source current (pin 3) VCC = 40V , TA = 25°C VID = −15mV to –5V, VO( pin 3) = 0.7V VID = 15mV to 5V, VO( pin 3) = 3.5V 65 0.3 -2 TEST CONDITIONS VO( PIN3) = 2.5V VO( PIN3) = 2.5V VO( PIN3) = 2.5V VCC = 7V to 40V LOW HIGH MIN TYP(1) 2 25 0.2 MAX 10 250 1 UNIT mV nA µA -0.3 VCC − 2 V 95 800 80 0.7 dB KHz dB mA mA ∆VO = 3V, VO = 0.5 to3. 5V 70 PWM Comparaor Section PARAMETER Input threshold voltage (pin 3) Input sink current (pin 3) TEST CONDITIONS Zero duty cycle VO( pin 3) = 0.7V 0.3 MIN TYP(1) 4 0.7 MAX 4.5 UNIT V mA Switching Characteristics PARAMETER Output Voltage rise time Output Voltage fall time Output Voltage rise time Output Voltage fall time TEST CONDITIONS Common-emitter configuration, See Test Circuit 3 Emitter-follower configuration, See Test Circuit 4 MIN TYP(1) 100 25 100 40 MAX 200 100 200 100 UNIT ns ns ns ns 3 GL494 Output Section PARAMETER Collector off-state current Emitter off-state current Collector-emitter Common-emitter Saturation voltage Emitter-follower Output control input current TEST CONDITIONS VCE = 40V, VCC = 40V VCC = VC = 40V, VE = 0 VE = 0, I C = 200mA VC = 15V, I E = −200mA VI = Vref 1.1 1.5 MIN TYP(1) MAX UNIT 2 100 -100 1.3 2.5 3.5 mA mA mA V Total Device PARAMETER Standby supply current Average supply current Notes: (1) (2) (3) All typical values except for temperature coefficients are at TA = 25 °C Duration of the short circuit should not exceed one second. Standard deviation is a measure of the statistical distribution about the mean as derived from the formula TEST CONDITIONS All other inputs & Outputs open V( pin 4) = 2V See Test circuit 1 VCC = 15V VCC = 40V MIN TYP(1) 6 9 7.5 MAX 10 15 UNIT mA mA mA σ= ∑ (X n − X ) 2 n =1 N N −1 4 GL494 Parameter Measurement Information 1.Dead time and Feedback Control Vcc=15V 150Ω 150Ω 2W 2W TEST INPUTS DEAD TIME (4) (8) C1 (9) E1 12kΩ FEEDBACK (3) Re (6) Cr (5) (11) C2 0.01µF (+) (16) ERROR (12) E2 (-) (15) AMP (+) (1) ERROR (-) (2) AMP (14) REF OUTPUT 50kΩ CONTROL GND (7) OUT (13) VOLTAGE AT C1 VOLTAGE AT C2 VOLTAGE AT CT THRESHOLD VOLTAGE DEAD-TIME CONTROL INTPUT FEEDBACK DUTY CYCLE Vcc 0 Vcc 0 OUTPUT 1 OUTPUT 2 0V 0.7V 0% MAX THRESHOLD VOLTAGE MAX 0% TEST CIRCUIT VOLTAGE WAVEFORMS 2. Error Amplifier Characteristics + V1 – ERROR AMPLIFIER UNDER TEST FEEDBACK TERMINAL + VREF – OTHER ERROR AMPLIFIER 3. Common-Emitter Configuration 15V (EACH OUTPUT CIRCUIT) 68Ω 2W OUTPUT 90% 90% CL=15pF (INCLUDES PROBE AND JIG CAPACITANCE) 10% 10% tr tf TEST CIRCUIT OUTPUT VOLTAGE WAVEFORM 5 GL494 4. Emitter-Follower Configuration (EACH OUTPUT EIRCUIT) 15V 90% 90% 10% OUTPUT 68Ω 2W CL=15pF (INCLUDES PROBE AND JIG CAPACITANCE) tr 10% tf TEST CIRCUIT OUTPUT VOLTAGE WAVEFORM Typical Performance Curves AVOL, OPEN-LOOP VOATAGE GAIN (db) FIGURE 1 – OSCILLATOR FREQUENCY versus TIMING RESISTANCE 0.001 µF Vcc=15V 100 90 80 70 60 50 40 30 20 10 0 1.0 10 100 1k 10k 100k 300k 100k FIGURE 2 – OPEN LOOP VOLTAGE GAIN AND PHASE versus FREQUENCY 20 0 10k AVOL Vcc=15V Vo=3V RL=2kΩ θ -20 -40 -60 -80 -100 -120 -140 -160 -80 1M CT=0.01 µF 1k 0.1 µF 100 30 1k 2k 5k 10k 20k 50k 100k 200k 500k 1M 0.1 µF RT, TIMING RESISTANCE (Ω ) f, FREQUENCY (Hz) %DT. PERCENT DEADTIME, EACH OUTPUT ACH OUTPUT FIGURE 3 – PERCENT DEAD TIME versus OSCILLATOR FREQUENCY 10 9 8 7 6 5 4 3 2 1 0 100 1k 10k 100k FIGURE 4 – PERCENT DUTY CYCLE versus DEAD-TIME CONTROL VOLTAGE 50 Vcc=15V Voc=Vref V(PIN4)=0V 40 30 CT=0.01 µF 1 2 Vcc=15V Voc=Vref 1) CT=0.01 RT=10k 2) CT=0.001 RT=30K 20 0.01 µF 10 0 0 1.0 2.0 3.0 3.5 fo, OSCILLATOR FREQUENCY (Hz) DEAD TIME CONTROL VOLTAGE (V) 6 GL494 1.9 1.8 FIGURE 5 – EMITTER-FOLLOWER CONFIGURATION OUTPUT-SATURATION VOLTAGE versus EMITTER CURRENT 1.3 1.2 FIGURE 6 – COMMON-EMITTER CONFIGURATION OUTPUT-SATURATION VOLTAGE versus COLLECTOR CURRENT VCE(SAT), SATURATION VOLTAGE (V) 1.7 1.6 1.5 1.4 1.3 1.2 1.1 0 50 100 150 VCE(SAT), SATURATION VOLTAGE (V) Vcc=15V 1.1 1.0 0.9 0.8 0.7 0.6 0.5 0 50 100 150 Vcc=15V 200 250 200 250 IE, EMITTER CURRENT (mA) Ic, COLLECTOR CURRENT (mA) FUGURE 7 – STANDBY-SUPPLY CURRENT versus SUPPLY VOLTAGE 8.0 Icc, SUPPLY CURRENT (mA) 7.0 6.0 5.0 4.0 3.0 2.0 1.0 0 0 5.0 10 15 20 25 30 35 40 Vcc, SUPPLY VOLTAGE (V) 7